Chevrolet 2004 Express Van Owner's Manual page 15

4. Push the pin with the handle marked "R" down until
it is in the retaining clip.
5. Push the pin with the handle marked "L" down until
it is in the retaining clip.
6. If the vehicle has a floor mat, put the flap back to
its original position.
7. Repeat this procedure for the other seat base.
8. Connect the quick-release latch plates for the
lap-shoulder belts by inserting the latch plates
into the buckles attached at the outboard positions
of the bench seat. Do not twist the belt.
9. Check that both locking pins are locked into place
before operating the vehicle.
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